; bin tree copy
(defun our-copy-tree (tr)
	(if (atom tr)
		tr
		(cons (our-copy-tree (car tr)) 
					(our-copy-tree (cdr tr)))))

(setf bintree
			'(a (
					 (b c) (
									(c d) e)))
			tree '(a b c (d (e f (g h)))))

(format t "~A:~%" tree)
(format t "~A~%" (our-copy-tree tree))
